The original plug or hole cover. Is originally White and the amount of light that it lets pass through grows algae on the opposite side of the plug. With this one printing it black or another dark color that will prevent light from coming through will keep the algae down.

Prusa

i3 MK3

No

Yes

.1 to .3

30%

I really don't like to design anything with support. But in this case it's necessary. I designed this with a minimal use of plastic.